
package com.oahcfly.chgame.util.aes;

import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

import com.badlogic.gdx.Application.ApplicationType;
import com.badlogic.gdx.Gdx;

/** AES加密器
 * 
 * @author Eric_Ni */
public class CHAESEncryptor {
	public static final String MAK = "RBCXF-CVBGR-382MK-DFHJ4-C69G8"; // AES加密的密钥

	/** <pre>
	 * 数据加密
	 * 
	 * date: 2014-12-20
	 * </pre>
	 * 
	 * @author caohao
	 * @param cleartext
	 * @return */
	public static String encodeData (String cleartext) {
		String dataString;
		try {
			dataString = encrypt(MAK, cleartext);
		} catch (Exception e) {
			Gdx.app.error("AES", e.getMessage());
			dataString = cleartext;
		}
		return dataString;
	}

	/** <pre>
	 * 解密数据
	 * 
	 * date: 2014-12-20
	 * </pre>
	 * 
	 * @author caohao
	 * @param encrypted
	 * @return */
	public static String decodeData (String encrypted) {
		String dataString;
		try {
			dataString = decrypt(MAK, encrypted);
		} catch (Exception e) {
			Gdx.app.error("AES", e.getMessage());
			dataString = encrypted;
		}
		return dataString;
	}

	/** AES加密 */
	public static String encrypt (String seed, String cleartext) throws Exception {
		byte[] rawKey = getRawKey(seed.getBytes());
		byte[] result = encrypt(rawKey, cleartext.getBytes());
		return toHex(result);
	}

	/** AES解密 */
	public static String decrypt (String seed, String encrypted) throws Exception {
		if (seed == null || "".equals(seed) || encrypted == null || "".equals(encrypted)) {
			return null;
		}
		byte[] rawKey = getRawKey(seed.getBytes());
		byte[] enc = toByte(encrypted);
		byte[] result = decrypt(rawKey, enc);
		return new String(result);
	}

	private static byte[] getRawKey (byte[] seed) throws Exception {
		KeyGenerator kgen = KeyGenerator.getInstance("AES");
		final int JELLY_BEAN_4_2 = 17;

		SecureRandom sr = null;

		if (Gdx.app.getType() == ApplicationType.Android) {
			if (Gdx.app.getVersion() >= JELLY_BEAN_4_2) {
				sr = SecureRandom.getInstance("SHA1PRNG", "Crypto");
			} else {
				sr = SecureRandom.getInstance("SHA1PRNG");
			}
		} else if (Gdx.app.getType() == ApplicationType.iOS) {
			sr = SecureRandom.getInstance("SHA1PRNG", "Crypto");
		} else {
			sr = SecureRandom.getInstance("SHA1PRNG");
		}

		sr.setSeed(seed);
		kgen.init(128, sr); // 192 and 256 bits may not be available
		SecretKey skey = kgen.generateKey();
		byte[] raw = skey.getEncoded();
		return raw;
	}

	private static byte[] encrypt (byte[] raw, byte[] clear) throws Exception {
		if (raw == null || clear == null) {
			return null;
		}
		SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
		Cipher cipher = Cipher.getInstance("AES");
		cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
		byte[] encrypted = cipher.doFinal(clear);
		return encrypted;
	}

	private static byte[] decrypt (byte[] raw, byte[] encrypted) throws Exception {
		SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
		Cipher cipher = Cipher.getInstance("AES");
		cipher.init(Cipher.DECRYPT_MODE, skeySpec);
		byte[] decrypted = cipher.doFinal(encrypted);
		return decrypted;
	}

	public static String toHex (String txt) {
		return toHex(txt.getBytes());
	}

	public static String fromHex (String hex) {
		return new String(toByte(hex));
	}

	public static byte[] toByte (String hexString) {
		if (hexString == null || "".equals(hexString)) {
			return null;
		}
		int len = hexString.length() / 2;
		byte[] result = new byte[len];
		for (int i = 0; i < len; i++) {
			result[i] = Integer.valueOf(hexString.substring(2 * i, 2 * i + 2), 16).byteValue();
		}
		return result;
	}

	private static String toHex (byte[] buf) {
		if (buf == null) return "";
		StringBuffer result = new StringBuffer(2 * buf.length);
		for (int i = 0; i < buf.length; i++) {
			appendHex(result, buf[i]);
		}
		return result.toString();
	}

	private final static String HEX = "0123456789ABCDEF";

	private static void appendHex (StringBuffer sb, byte b) {
		sb.append(HEX.charAt((b >> 4) & 0x0f)).append(HEX.charAt(b & 0x0f));
	}

	public static void main (String[] args) throws Exception {
		String dataString = "1234ddfd";
		System.out.println("加密前：" + dataString);
		System.out.println("加密后：" + encrypt(MAK, dataString));
		System.out.println("解密后：" + decrypt(MAK, (encrypt(MAK, dataString))));
	}
}
